Renal dysfunction or failure and, in particular, end-stage renal disease, causes the body to lose the ability to remove water and minerals and excrete harmful metabolites, maintain acid-base balance and control electrolyte and mineral concentrations within physiological ranges. Toxic uremic waste metabolites, including urea, creatinine, and uric acid, accumulate in the body's tissues which can result in a person's death if the filtration function of the kidney is not replaced.
Dialysis is commonly used to replace kidney function by removing these waste toxins and excess water. In one type of dialysis treatment—hemodialysis (HD)—toxins are filtered from a patient's blood externally in a hemodialysis machine. Blood passes from the patient through a dialyzer separated by a semi-permeable membrane from a large volume of externally-supplied dialysis solution. The waste and toxins dialyze out of the blood through the semi-permeable membrane into the dialysis solution, which is then typically discarded.
The dialysis solutions or dialysates used during hemodialysis typically contain sodium chloride and other electrolytes, such as calcium chloride or potassium chloride, a buffer substance, such as bicarbonate or acetate, and acid to establish a physiological pH, plus, optionally, glucose or another osmotic agent.
Another type of dialysis treatment is peritoneal dialysis (PD) that utilizes the patient's own peritoneum, a membranous lining of the abdominal body cavity. With its good perfusion properties, the peritoneum is capable of acting as a natural semi-permeable membrane for transferring water and waste products to a type of dialysate solution known as PD solution introduced temporarily into the patient's abdominal cavity. An access port is implanted in the patient's abdomen and the PD solution is infused usually by a pump into the patient's abdomen through a patient line and left to dwell for a period of time and then drained out. This procedure is usually repeated multiple times for a complete treatment. PD machines, such as Automated PD (APD) machines or PD cyclers, are designed to facilitate or control the PD process so that it can be performed at home without clinical staff in attendance.
Dialysis machines are typically equipped with interfaces for receiving inputs and providing information to users.